9 research outputs found

    Cavovarus Foot Surgery Including a Peroneus Longus Transfer: A 2- to 6-Year Follow-up

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    Background: The primary aim of this longitudinal study was to describe patient satisfaction and clinical outcome at least 2 years following cavovarus foot surgery, utilizing a peroneus longus to brevis transfer, lateral ligament reconstruction, and corrective osteotomies of the first metatarsal, occasionally with the added calcaneal osteotomy. Methods: Sixteen patients (17 feet) were examined in 2010-2012, 3.5 (range, 2-6.5) years after cavovarus foot surgery performed in 2004-2010 utilizing a peroneus longus to brevis transfer, lateral ligament reconstruction, and osteotomy of the first metatarsal with or without additional calcaneal osteotomy. The mean age at surgery was 45 years. Evaluation at baseline before surgery and at follow-up assessed patient satisfaction, using the American Orthopaedic Foot & Ankle Society (AOFAS) hindfoot score. At follow-up, visual analog scale (VAS) score for pain at walking was recorded, and a clinical and radiographic evaluation was included. Results: The mean AOFAS score improved from 57 (SD 11) to 83 (SD 12.5) points, with an average score improvement of 25 score points (95% confidence interval 16-35, P < .0001). Postoperative VAS score for pain at walking was mean 2 (range, 0-6). All feet had a residual cavovarus both clinically and on the radiographs. Conclusion: Patient satisfaction and clinical outcome was shown to improve pre- to postsurgery at intermediate follow-up after peroneus longus to brevis transfer and metatarsal osteotomies with or without additional calcaneal osteotomies as part of a cavovarus foot correction. Level of Evidence: Level IV, case series

    Precision Measurement of the Helium Flux in Primary Cosmic Rays of Rigidities 1.9 GV to 3 TV with the Alpha Magnetic Spectrometer on the International Space Station

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    Knowledge of the precise rigidity dependence of the helium flux is important in understanding the origin, acceleration, and propagation of cosmic rays. A precise measurement of the helium flux in primary cosmic rays with rigidity (momentum/charge) from 1.9 GV to 3 TV based on 50 million events is presented and compared to the proton flux. The detailed variation with rigidity of the helium flux spectral index is presented for the first time. The spectral index progressively hardens at rigidities larger than 100 GV. The rigidity dependence of the helium flux spectral index is similar to that of the proton spectral index though the magnitudes are different. Remarkably, the spectral index of the proton to helium flux ratio increases with rigidity up to 45 GV and then becomes constant; the flux ratio above 45 GV is well described by a single power law

    Precision Measurement of Cosmic-Ray Nitrogen and its Primary and Secondary Components with the Alpha Magnetic Spectrometer on the International Space Station

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    A precision measurement of the nitrogen flux with rigidity (momentum per unit charge) from 2.2 GV to 3.3 TV based on 2.2×10[superscript 6] events is presented. The detailed rigidity dependence of the nitrogen flux spectral index is presented for the first time. The spectral index rapidly hardens at high rigidities and becomes identical to the spectral indices of primary He, C, and O cosmic rays above ∼700  GV. We observed that the nitrogen flux Φ[subscript N] can be presented as the sum of its primary component Φ[subscript N][superscript P] and secondary component Φ[subscript N][superscript S], Φ[subscript N] = Φ[subscript N][superscript P]+ Φ[subscript N][superscript S], and we found Φ[subscript N] is well described by the weighted sum of the oxygen flux Φ[subscript O] (primary cosmic rays) and the boron flux Φ[subscript B] (secondary cosmic rays), with Φ[subscript N][superscript P] = (0.090±0.002) × Φ[subscript O] and Φ[subscript N][superscript S] = (0.62±0.02) × Φ[subscript B] over the entire rigidity range. This corresponds to a change of the contribution of the secondary cosmic ray component in the nitrogen flux from 70% at a few GV to <30% above 1 TV

    Observation of the Identical Rigidity Dependence of He, C, and O Cosmic Rays at High Rigidities by the Alpha Magnetic Spectrometer on the International Space Station

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    We report the observation of new properties of primary cosmic rays He, C, and O measured in the rigidity (momentum/charge) range 2 GV to 3 TV with 90×106 helium, 8.4×106 carbon, and 7.0×106 oxygen nuclei collected by the Alpha Magnetic Spectrometer (AMS) during the first five years of operation. Above 60 GV, these three spectra have identical rigidity dependence. They all deviate from a single power law above 200 GV and harden in an identical way

    Precision Measurement of the Proton Flux in Primary Cosmic Rays from Rigidity 1 GV to 1.8 TV with the Alpha Magnetic Spectrometer on the International Space Station

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    Precision Measurement of the (e++e−)\left({e}^{+}+{e}^{-}\right) Flux in Primary Cosmic Rays from 0.5 GeV to 1 TeV with the Alpha Magnetic Spectrometer on the International Space Station

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    We present a measurement of the cosmic ray (e+ + e−) flux in the range 0.5 GeV to 1 TeV based on the analysis of 10.6 million (e+ + e−) events collected by AMS. The statistics and the resolution of AMS provide a precision measurement of the flux. The flux is smooth and reveals new and distinct information. Above 30.2 GeV, the flux can be described by a single power law with a spectral index γ=−3.170±0.008(stat+syst)±0.008(energy scale)
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